Heaven is eternal and Earth everlasting. They can be eternal and everlasting because they do not exist for themselves, And for this reason can exist forever.
At the moment that we persuade a child, any child, to cross that threshold, that magic threshold into a library, we change their lives forever, for the better
The Expulsion from Paradise is eternal in its principal aspect: this makes it irrevocable, and our living in this world inevitable, but the eternal nature of the process has the effect that not only could we remain forever in Paradise, but that we are currently there, whether we know it or not.
One hopes, of course, that a relationship grows and becomes a deep and wonderful marriage and friendship that lasts forever. But that's not always the case.
If you go searching for the Great Creator, you will come back empty-handed. The source of the universe is ultimately unknowable, a great invisible river flowing forever through a vast and fertile valley. Silent and uncreated, it creates all things.